氯化胆碱-乙二醇低共熔溶剂中Sn2+/Sn的电化学行为

来源期刊:中南大学学报(自然科学版)2018年第9期

论文作者:李坚 苏波 华一新 徐存英 李艳 艾刚华

文章页码:2129 - 2137

关键词:低共熔溶剂;氯化胆碱-乙二醇;电化学;电结晶;形核机理

Key words:deep eutectic solvent; choline chloride-ethylene glycol; electrochemistry; electrocrystallization; nucleation mechanism

摘    要:采用循环伏安法和计时安培法研究在氯化胆碱-乙二醇低共熔溶剂SnCl2·2H2O/[1ChCl:2EG] DES中,Sn2+/Sn的电化学行为和Sn的电结晶形核机理。研究结果表明:Sn的电沉积需要一定的过电位,并随温度的升高,所需的过电位减小;获得323 K时的传递系数α为0.35,Sn2+的扩散系数为1.628×10-6 cm2/s;在303~343 K内,Sn2+在SnCl2·2H2O/[1ChCl:2EG] DES中的电还原反应属于受扩散控制的准可逆过程;当阴极施加电位较小(较正)时,Sn在玻碳电极上的电结晶过程为受扩散控制的三维瞬时形核,当阴极施加电位较大(较负)时,Sn的电结晶过程更趋向于三维连续形核。

Abstract: The electrochemical behaviors of Sn2+/Sn and the nucleation mechanism of the electrocrystallization of tin in choline chloride-glycol deep eutectic solvents SnCl2·2H2O/[1ChCl:2EG] DES were studied by means of cyclic voltammetry and chronoamperometry. The results show that a certain overpotential is required for tin electrodeposition and the required overpotential decreases with the increase of temperature. The transfer coefficient α is calculated to be 0.35 and the diffusion coefficient of Sn2+ is estimated to be 1.628×10-6 cm2/s at 323 K. The electroreduction of Sn2+ in SnCl2 ·2H2O/[1ChCl:2EG] DES is a quasi-reversible process controlled by diffusion at 303-343 K. When the applied potential on cathode is lower(more positive), the initial electrocrystallization process of Sn on a GC electrode is found to be a three-dimensional instantaneous nucleation under diffusion control by chronoamperometry. When the applied potential on cathode is larger(more negative), it is more likely to be three-dimensional progressive nucleation.

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